Chairs often include a base that supports a seat and/or a backrest. Some types of chairs are configured as stools. Some types of stools may not include a backrest. Of course, other types of chairs may also be configured to not include a backrest. Examples of chairs, stools, and other types of seating devices may be appreciated from U.S. Pat. Nos. 8,646,841, 8,136,876, 7,478,878, 6,834,916, 5,112,103, 4,130,263, 3,312,437, and D664,779. Other types of chairs such as lounge chairs or office chairs may have a backrest. Examples of such chairs may be appreciated from U.S. Pat. Nos. 8,764,117, 8,663,514, 8,480,171, 8,220,872, 8,216,416, 8,167,373, 8,157,329, 8,029,060, 7,887,131, 7,198,329, 6,997,511, 6,824,218, 6,817,667, 5,683,139, and 4,738,487 and U.S. Pat. App. Pub. Nos. 2003/0168901, 2006/0006715, and 2008/0290712.